An Implantable pulse generators (IPGs) such as pacemakers and implantable cardioverter defibrillators (ICDs), which are used in the treatment of cardiac conditions, and neuromodulators or neurostimulators, which are used in chronic pain management or the actuation and control of other body systems, commonly include a housing, feedthrus, and a connector assembly that is enclosed in a header. Electrical stimulation originating in the housing is led to the connector assembly through feedthrus. The connector assembly serves to transmit electrical signals out of the IPG and to a lead electrically connected to the connector assembly, the lead transmitting electrical signals between the IPG and patient tissue.
Current header casting manufacturing processes and the associated methods of assembling the header and its enclosed connector assembly and electrical connection assembly onto the housing require multiple operations, are skill intensive, and unavoidably time consuming.
First, a header having cylindrical passages or openings generally matching the shape of a connector assembly is cast in epoxy. The header may have additional openings or passageways for electrically coupling the connector assemblies with a housing of an IPG. Second, the connector assemblies are positioned within the passages or openings of the pre-cast header. The openings are slightly larger than the connector assemblies so that the connector assemblies can be manually inserted into the openings. Third, electrical connections may be made (e.g., welding) between the connector assemblies and other components within the header that route the electrical signals between the connector assemblies and the housing. For example, an electrical connection assembly may be positioned within a particular opening or passage of the header such that it is in contact with the connections of the connection assemblies while protruding from an opposite end from the header so that it can be coupled with the feedthrus and into the header. Fourth, an overmolding process is done to securely affix the connector assemblies to the pre-cast header. More particularly, the overmolding process gap-fills the space between the openings in the pre-cast header and the inserted connector assemblies. The particular overmolding process may be injecting a thermosetting polymer (e.g., an epoxy) to a portion of the header to backfill the space between the openings and the connector assemblies. This overmolding or backfill process creates attachment and electrical sealing between the connector assemblies and the electrical connection assembly within the header. The backfill process is lengthy and expensive and may involve mold set-up, mold pre-heat, epoxy dispense, epoxy curing, and mold breakdown.
There is a need in the art for systems and methods that eliminate the backfill process. Additionally, there is a need in the art for connector assemblies that are suitable for injection molding of the header over the connector assemblies and electrical connector assembly.